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EFFECTS OF CO2 AND O3 ON WATER BALANCE FOR A PONDEROSA PINE PLANT/LITTER/SOIL SYSTEM
Citation:
Olszyk, D M., D T. Tingey, M G. Johnson, AND R. S. Waschmann. EFFECTS OF CO2 AND O3 ON WATER BALANCE FOR A PONDEROSA PINE PLANT/LITTER/SOIL SYSTEM. Presented at Ecological Society of America annual meeting, Madison, WI, August 4-10, 2001.
Description:
There are numerous reports on the individual effects of CO2 and O3 alone on individual plants, but very little information on the interactive effects of these pollutants, especially on indicators of ecosystem function such as water cycling. We determined the effects of elevated CO2 (+280 ppm above ambient) and elevated O3 (SUM06 of 10.4 to 26.1 ppm ? hr) on the water balance for a mesocosm-scale ponderosa pine seedling/litter/soil system. The trees were grown for three seasons in outdoor, sunlit, chambers. All treatments received the same amount of irrigation, which varied to provide seasonal soil moisture levels representative of ponderosa pine growing areas, i.e. soils were near saturation in the winter, were allowed to dry down during the growing season (spring and summer), and increased in moisture in the fall. Water inputs and outputs to the system, and change in soil moisture storagewere measured on a weekly basis. Over the third growing seaso,n elevated O3 reduced the loss of water from the system whereas elevated CO2 had no effect on water loss from the system. The water balance data were compared to other system physical and biological data to evaluate possible factors responsible for treatment effects on water cycling.